8 cardinals, still alive and well, they LOVED the blood worm I got! It was a frozen cube that I defrosted for a few seconds in a glass and then plopped into the tank.
I recommend completely thawing frozen food before it enters the tank. There is no scientific evidence of frozen food being lethal, at least not that I know of, but it only makes sense to completely thaw it first. Fish in the tropics do not eat frozen foods, and you know how you can feel something you've swallowed that is frozen. I put my frozen daphnia and bloodworms into separate sauce dishes, run hot water from the tap, then feed with a type of baster I made from airline tubing. By the time the food gets in the tank, it is no warmer than the tank water.
AS for adding fish. I went to the LFS and they only had 2 albino cory, 2 panda cory, and 2 "stone catfish" which I'd never seen before and looked awesome, but wanted to ask about.
I'll need the scientific name, or a photo, maybe a description will do, to track down "stone catfish." I am only guessing that it might be some species of loricariid, or perhaps a Hillstream loach species. No point in guessing at issues without knowing the species.
Do cory cats of varying species mix well, meaning, if I have 2 of one type, and 2 of another, does that 'count' as a school of 4, or do they treat each other as disparate fishes? Weird question I guess.
No, it is not a weird question, it is one frequently asked here. While having at least five of a species is preferable, where tank space permits, you can mix species to reach this number.
Shoaling fish require a number of their own species for various reasons that are programmed into their DNA through evolution.
Corydoras species are closely related (though there are probably nine different genera within the present polyphletic genus
Corydoras) and so peaceful that they easily mix in an aquarium. In their habitats, they tend to be isolated as one species, but there are watercourses where two or three species co-exist, though just how much mixing together is questionable. But to the aquarium...if there is some detrimental issue in having say three of one species and three of another as opposed to six of one species, I cannot say; none of us knows how this impacts the fish's thinking. We do know that the more there are, single or mixed species, the less stressed the fish appear to be, so the overall number is perhaps the most important aspect.
I have some 50 cories in my 70g, representing 12 species. I have 10
C. duplicareus (may be
C. adolfoi, I am not going to kill one to examine its pectoral fin under the microscope for serrations to ascertain which), 7
C. similis, 7
C. panda, 6
C. reticulatus, 4
C. sterbai, then the remaining seven species are either single fish, two or three. This comes about when stores only have such numbers and I buy them all, and being wild caught one may not see the species for some time after. Anyway, they seem very happy together, and I frequently see fish of differing species shoaling around and even going through spawning motions (cross-species, the
C. sterbai and
C. duplicareus do this a lot). I always try to get five of a species when I can.
In your 10 gallon tank, five or six is max, and some will likely not agree even with having these in a small tank. But it can work, depending upon the species and other fish and your maintenance. Certainly no fewer than five, or forget cories.
I am concerned about my water parameters for corys. the guy at the LFS said my pH is too low for them, and though they DO like soft water, my extremely soft water combined with the pH might be lethal for them.
This is possible. I just tested the pH in my cory tank and it is at 6.0 using the API test, but of course it could be much lower as 6 is the lowest the test will go. I know this tank and others do get to 5 and perhaps even lower. My large weekly water changes work to keep it higher than it would otherwise be. I am hesitant to say "OK" with the risk.
I assume my "column swimmer" fish is full, being 8 cardinals, and really the only thing left to go into the tank are cory cats, and then it's done.
I've been doing 25% water changes weekly and the parameters look good, aside from that ever-weird low pH (was about 4.0 - 4.5 today according to three different testing types)
Yes, 8 cardinals is it, but remember with cories you must have five. And remember that while 8 juvenile cardinals and five juvenile cories don't look like much in a 10g, they will grow and the impact on the biological system increases, and the physical space decreases as the fish get larger. And I would certainly increase the volume of the water change to 50% once a week.
